Some vehicles have an authorization system to allow user access to the vehicles based on identification of a user. For example, an authorization system unlocks a vehicle door upon only one successful identification of the user. There may be an issue for such authorization system. For example, when the user is far away from the vehicle, other people can get into the vehicle. In another example, an authorization system unlocks the vehicle door based on successful identification of the user twice. In such system, the first successful identification of the user unlocks a vehicle door, and the second successful identification of the user allows operation of an engine or a starter. The second identification recognizes the user based on further comparison of a captured image of the user inside the vehicle and a stored image in the authorization system. Identification failure can occur due to the image quality if the image is taken in a dark environment and a camera is too close to the user, resulting in low resolution image. Therefore, there is a need for an authorization system with desired identification success rate.